On 9/2/24 2:01 PM, Raphael Moreira Zinsly wrote:
I must be missing something. All the tests have bit31 on. But I don't think this synthesis is valid when bit31 is on and the code seems to check this. What am I missing?Improve handling of constants where the high half can be constructed by inverting the lower half. gcc/ChangeLog: * config/riscv/riscv.cc (riscv_build_integer): Detect constants were the higher half is the lower half inverted. gcc/testsuite/ChangeLog: * gcc.target/riscv/synthesis-15.c: New test. --- gcc/config/riscv/riscv.cc | 30 +++++++++++++++++++ gcc/testsuite/gcc.target/riscv/synthesis-15.c | 26 ++++++++++++++++ 2 files changed, 56 insertions(+) create mode 100644 gcc/testsuite/gcc.target/riscv/synthesis-15.c diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index 64d5611cbd2..9eb62e34b5b 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -1343,6 +1343,36 @@ riscv_build_integer (struct riscv_integer_op *codes, HOST_WIDE_INT value, alt_codes[alt_cost - 1].use_uw = false; alt_codes[alt_cost - 1].save_temporary = false;+ memcpy (codes, alt_codes, sizeof (alt_codes));+ cost = alt_cost; + } + } + } + + if (cost > 5 && !bit31) + { + /* For constants where the upper half is the lower half inverted we can flip + it with an xor and do a shift 32 followed by an or. */ + if (hival == (~loval & 0xffffffff)) + { + alt_cost = 3 + riscv_build_integer_1 (alt_codes, + sext_hwi (loval, 32), mode); + if (alt_cost < cost) + { + alt_codes[alt_cost - 4].save_temporary = true; + alt_codes[alt_cost - 3].code = XOR; + alt_codes[alt_cost - 3].value = -1; + alt_codes[alt_cost - 3].use_uw = false; + alt_codes[alt_cost - 3].save_temporary = false; + alt_codes[alt_cost - 2].code = ASHIFT; + alt_codes[alt_cost - 2].value = 32; + alt_codes[alt_cost - 2].use_uw = false; + alt_codes[alt_cost - 2].save_temporary = false; + alt_codes[alt_cost - 1].code = CONCAT; + alt_codes[alt_cost - 1].value = 0; + alt_codes[alt_cost - 1].use_uw = false; + alt_codes[alt_cost - 1].save_temporary = false; + memcpy (codes, alt_codes, sizeof (alt_codes)); cost = alt_cost; } diff --git a/gcc/testsuite/gcc.target/riscv/synthesis-15.c b/gcc/testsuite/gcc.target/riscv/synthesis-15.c new file mode 100644 index 00000000000..eaec6119a72 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/synthesis-15.c @@ -0,0 +1,26 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target rv64 } */ +/* We aggressively skip as we really just need to test the basic synthesis + which shouldn't vary based on the optimization level. -O1 seems to work + and eliminates the usual sources of extraneous dead code that would throw + off the counts. */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-O2" "-O3" "-Os" "-Oz" "-flto" } } */ +/* { dg-options "-march=rv64gc" } */ + +/* Rather than test for a specific synthesis of all these constants or + having thousands of tests each testing one variant, we just test the + total number of instructions. + + This isn't expected to change much and any change is worthy of a look. */ +/* { dg-final { scan-assembler-times "\\t(add|addi|bseti|li|pack|ret|sh1add|sh2add|sh3add|slli|srli|xori|or)" 60 } } */ + +unsigned long foo_0x4afe605fb5019fa0(void) { return 0x4afe605fb5019fa0UL; } +unsigned long foo_0x07a80d21f857f2de(void) { return 0x07a80d21f857f2deUL; } +unsigned long foo_0x6699f19c99660e63(void) { return 0x6699f19c99660e63UL; } +unsigned long foo_0x6c80e48a937f1b75(void) { return 0x6c80e48a937f1b75UL; } +unsigned long foo_0x47d7193eb828e6c1(void) { return 0x47d7193eb828e6c1UL; } +unsigned long foo_0x7c627816839d87e9(void) { return 0x7c627816839d87e9UL; } +unsigned long foo_0x3d69e83ec29617c1(void) { return 0x3d69e83ec29617c1UL; } +unsigned long foo_0x5bee7ee6a4118119(void) { return 0x5bee7ee6a4118119UL; } +unsigned long foo_0x73fe20828c01df7d(void) { return 0x73fe20828c01df7dUL; } +unsigned long foo_0x0f1dc294f0e23d6b(void) { return 0x0f1dc294f0e23d6bUL; }
jeff
